This is a multi-center study of normal structural and metabolic brain development in infants and children, being sponsored by NINDS, NIMH and NICHD. Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) will be used to characterize brain development in relationship to behavior and cognition from ages 0 through 18 years, supplemented by diffusion tensor imaging (DTI) for ages 0 through 4 years. The project is planned for six years and involves a longitudinal design, repeated behavioral testing, and rescanning of subjects. This project will result in a representative, reliable and adequate database with which to characterize normal brain development, construct growth curves with which to evaluate individual brains, provide potential control data for studies of patients, and create developmentally-sensitive image analysis tools. A data sharing plan will be implemented to make this resource available to the medical and research community.